This invention relates to a liquid level indicator which is particularly useful for portable toilets.
A number of commonly assigned patents illustrate portable toilets of the type comprising a seat section mounted on a holding tank section. The seat section comprises a toilet bowl and a flush water storage reservoir. In use flush water is introduced into the toilet bowl through a suitable mechanism such as a hand-operated pump. After use a valve which is disposed between the bowl and the holding tank section is operated to allow the contents of the bowl to be deposited into the holding tank section. In this way the waste materials are accumulated in the holding tank section until the opportunity presents itself for dumping the contents of the holding tank section at an appropriate sanitary disposal station. In the type of portable toilet just described the holding tank section is separably mounted to the seat section so that only the holding tank section need be removed and dumped. Other designs of portable toilets may not be of this particular construction and may require the entire portable toilet to be brought to a disposal station for dumping.
In certain instances it may be either difficult or inconvenient to determine how full the holding tank is. In the aforementioned type of portable toilets it is obviously possible for one to open the valve and look into the holding tank. Needless to say this may be a rather unpleasant task due to exposure of the contents of the holding tank when the valve is open. Furthermore because the observer is looking down onto the surface of the contents of the holding tank it may be difficult to judge the level of the content. This is especially the case in confined and/or low light quarters where such toilets are often located.
Attempts to judge the contents of the holding tank by weight are also difficult. This is particularly the case for a portable toilet where the holding tank and seat sections are not separable. In the case of separable seat and holding tank sections the holding tank section may be separated and its contents judged after separation. This however is often an inconvenience since it requires that the seat section be removed; it is also only an approximation.
The present invention is, in one respect, directed to a new and improved arrangement for ascertaining how full the holding tank is without the inconvenience and unpleasantries often associated with prior procedures. More specifically the present invention is directed to a liquid level indicator which is associated with the holding tank section so as to provide a visible indication of the level of liquid within the holding tank without the need to do anything to the portable toilet. Due to the manner in which portable toilets are used the inclusion of a liquid level indicator requires a degree of sophistication which may not be readily appreciated. Because of the nature of waste materials it is important that the indicator and associated mechanism be impervious to the waste contents. From the standpoint of user acceptance it is desirable that waste material be excluded from view when one is viewing the indicator. From the standpoint of functionality, it is important that waste material be prevented from intruding into the indicator and associated mechanism where it might interfere with an accurate reading. It is also vital that the mounting of the indicator be leakproof for reasons of sanitation and user acceptance. Another consideration is that the indicator be of economical construction in relation to the cost of the toilet.
The present invention provides a liquid level indicator for a portable toilet which meets these objectives in an admirable fashion. The indicator and associated mechanism comprise a relatively small number of parts; are protected from and generally immune to the contents of the holding tank; mount on the tank without the use of any separate fasteners such as screws, bolts, etc.; have a leak-proof mounting because no holes through the tank wall are needed; and provide an accurate indication of the liquid level within the holding tank.
More specifically, in the preferred embodiment of the invention which is disclosed herein an upwardly open receptacle is provided in the top wall of the holding tank and is closed by a bezel and lens assembly to form a space for an indicator wheel which is journaled for rotation about a horizontal axis. The lower portion of the wheel is disposed within the receptacle and an upper portion of the wheel is disposed for view through the lens. A magnet is mounted on the wheel in radially spaced relation to its axis of its rotation and within the receptacle.
An operator for the wheel is disposed within the holding tank adjacent the receptacle. The operator comprises a float arm assembly which mounts on the holding tank for arcuate motion about a horizontal axis of rotation. The float arm assembly contains a float element and a magnet both in radially spaced relation to the axis of the float arm assembly. The level of liquid material within the tank angularly positions the float arm assembly about its axis. This also is effective to correspondingly angularly position the float arm assembly magnet. The magnet of the float arm assembly and that of the wheel are arranged such that there is an attractive force between the two. The arcuate motion of the float assembly magnet corresponds generally with that of the wheel magnet about the wheel's axis. The holding tank wall is of a nonmagnetic material. Hence, the angular position of the wheel is controlled by the float via the magnetic coupling passing through the holding tank wall. A suitable indicia is provided on the wheel which when viewed through the lens provides a visible indication of the level of liquid material within the holding tank.
The foregoing features, advantages and benefits of the invention, along with additional ones, will be seen in the ensuing description and claims which should be considered in conjunction with the accompanying drawings. The drawings disclose a preferred embodiment of the invention according to the best mode contemplated at the present time in carrying out the invention.